The invention relates to a tractor cabin comprising at least one fairing with an air deflector and an air deflector for a tractor cabin.
It is known in the art to provide fairings for tractor cabins of tractor trailer combinations in order to improve the aerodynamic properties and thus reduce fuel consumption of tractor trailer combinations. Usually, a deflector hood is installed on an upper portion of the tractor cabin and side air deflectors are provided for improving the wind flow around the tractor and a trailer connected to the tractor.
U.S. Pat. No. 5,536,062 A1 discloses fairings for a tractor trailer combination wherein segmented panels form an air deflector comprising opposing segmented side pivotal panels, opposing segmented upper side pivotal panels and opposing segmented lower side pivotal panels. The use of wing members either fixed or variably mounted on or about the various panels allows conditioning the wind flow.
It is desirable to provide a tractor cabin, particularly for a tractor trailer combination, with improved aerodynamic behaviour. It is desirable to provide an air deflector for a tractor cabin with improved aerodynamic behaviour.
A tractor cabin according to an aspect of the invention comprises a frame with an upper cabin portion, a front cabin portion, a rear cabin portion and side cabin portions and at least one fairing connected to the frame, wherein the at least one fairing comprises at least one air deflector, wherein the deflector is adjustable in its tilt angle with respect to the frame. The deflector comprises a deflector body with a variable deflection along a longitudinal elongation of the deflector body. This allows having locally different deflection along the longitudinal elongation of the deflector and adjusting the deflection as a function of operation parameters of the tractor cabin, for example, there are different legal limits for the width of the tractor cabin in various countries. The invention allows, according to aspects thereof, for adjustment of the span width of side air deflectors of a fairing on the fly according to an actual legal limit when the tractor trailer combination travels from one country to another country. Preferably, the longitudinal elongation of the deflector is parallel to an edge of the cabin frame to which the deflector is coupled, e.g. the longitudinal elongation (or length) of a side air deflector is parallel to a vertical edge of the cabin frame, whereas the longitudinal elongation of a deflector on the upper cabin portion is parallel to a horizontal edge of the cabin frame. The transversal elongation represents the width of the deflector.
Preferably, at least a portion of the deflector body can be formed of a torsional flexible material. Preferably, the side air deflector as a whole is made of such a torsional flexible material. By coupling appropriate actuators to the deflector at convenient locations, the deflection of the deflector can be varied in fine and/or coarse increments along the longitudinal deflector elongation.
The deflector can comprise at least one portion formed integrally of one piece with the deflection of the portion being variable along the longitudinal elongation of the deflector. In a convenient embodiment, the complete bodies of the side air deflectors are integrally formed of one piece each.
Actuator means can conveniently be provided for varying the tilt angle and/or the curvature of the deflector with respect to the frame. The deflector can be tilted outwards with respect to the cabin frame to provide a wider span width or it can be tilted inwards depending on operation parameters of the vehicle, e.g. on a vehicle speed, a wind speed or a legal limit of the allowable span width of the tractor and the side air deflector connected to the cabin, respectively, and the like.
Preferably, the tilt angle of the deflector is selectively switchable between a minimum and a maximum angle at different portions of the deflector body. By changing the tilt angle, the deflector span width, e.g. of the side air deflector, can be increased or decreased without varying the curvature of the deflector and, vice versa, by changing the curvature, the deflector span width can be increased or decreased without changing the tilt angle. This can be done differentially along the longitudinal elongation of the deflector. However, both parameters can also be varied simultaneously as well. The deflector can also be an air deflector on the upper cabin portion. A skilled person will choose a variation appropriate to the actual situation and/or result which shall be achieved by varying the deflector.
The curvature of the deflector can be variable, particularly continuously variable. This can be generated by an appropriate distribution of actuators on or in the deflector body.
Preferably, the deflector can be a side air deflector which is connected to a deflector hood on the upper cabin portion. Alternatively or additionally, the deflector can also be an air deflector on the upper cabin portion.
As side air deflector, the deflector portion formed integrally of one piece can favourably span a major portion of a vertical edge of the frame. A rigid deflector portion can be arranged between the deflector hood and the deflector with variable deflection. The rigid portion can be an integral part of the otherwise torsional flexible deflector body. By this embodiment it can avoided to hinge a separate side air deflector to the rigid part above it, thus avoiding a detrimental effect on the wind flow such as aerodynamic drag. A mismatch in the joint area between the adjustable portion and the upper fixed portion can be obviated.
According to another aspect of the invention, an air deflector is suggested, particularly for a tractor cabin, with a longitudinal elongation and a transversal elongation, comprising a deflector body with a variable deflection along the longitudinal elongation of the deflector body. Thus, a span width of a deflector can easily be adjusted to a desired value.
Preferably, at least a portion of the deflector body is formed of a torsional flexible material. Thus it is possible to provide a deflector causing no or only minor aerodynamical drag due to a mismatch between deflector portions of different deflection and/or orientation.
Favourably, at least one portion can be formed integrally of one piece with the deflection of the portion being variable along the longitudinal elongation of the deflector.
According to an advantageous embodiment, actuator means can be provided for varying a tilt angle and/or a curvature of the deflector body. The actuator means can be at least any one of the group of e.g. pneumatic actuators distributed on or in the deflector body comprising inflatable cavities and/or ducts which cause the deflector body to bend when activated and to relax when deactivated (or vice versa); and/or hydraulic or pneumatic drives attached to the deflector body causing the body to tilt with respect to the cabin frame; and/or electric nanoactuators such as nanostructures, e.g. nanotubes, made of Buckminster fullerene materials which can be activated by application of an electrical voltage and which can extend or contract and bend or tilt the deflector body; and/or piezoelectric actuators, and/or elastomer material which can be reversibly deformed; and/or shape memory materials, which can change shape, dimension and/or stiffness by experiencing an activation signal; and/or a elastically deformable plate material with an hydraulic adjusting mechanism for bending or unbending the material; and the like.
Preferentially, the tilt angle of the deflector can be selectively switchable between a minimum and a maximum angle at different portions of the deflector body. Thus, the span widths of side air deflectors can be switched between desired values. It is possible to provide different tilt angles along the longitudinal elongation of the deflector.
Additionally or alternatively, the curvature of the deflector can be variable, particularly continuously variable, along the longitudinal elongation.
It is understood that while the invention is described mounted on a tractor having a trailer pivotally and detachably mounted thereto that the invention can be applicable to other types of trucks such as van type trucks, having the trailer section rigidly and permanently attached to the tractor section.
In the drawings, equal or similar elements are referred to by equal reference numerals.